10 Strange Skin Problems That Could Be a Sign of a Serious Disease

Updated: Aug. 02, 2023

Your skin can show signs of what's happening inside your body, from diabetes to cancer, tick bites, and more.

What your skin shows

Almost anyone who’s ever gotten a rash from accidentally eating something they were allergic to knows: your skin is your body’s largest organ, and it can be a window into the state of your internal health. In fact, says Whitney High, MD, a board-certified dermatologist and vice-director of the dermatopathology laboratory at the University of Colorado School of Medicine in Denver: “All of our organ systems are related.”

To Dr. High’s point, from acne or rosacea to signs of skin cancer, what’s going on in your body can affect your skin—and vice versa. Here are some strange skin problems that could be a sign of a serious disease.

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Acrochordon -- a skin tag

You notice lots of skin tags popping up

A few of these skin growths here or there is normal, but numerous skin tags that begin popping up could indicate type 2 diabetes. They’re spurred on by insulin-like growth factor 1, a protein involved in diabetes that stimulates skin overgrowth, says Rachel Reynolds, MD, a dermatologist with Beth Israel Deaconess Medical Center in Boston, Massachusetts. Other signs of type 2 include increased thirst, slow healing wounds, and increased hunger. Here’s the only way to get rid of skin tags, according to a dermatologist.

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macro image of an ugly white head zit, pictured with a narrow depth of field
Stephen Gibson/Shutterstock

You’re breaking out like crazy

Adult acne is very common…but when it’s a fairly new development, pay attention. Adult acne a skin change that could be a sign of something more serious.

For example, acne can be a symptom of polycystic ovary syndrome (PCOS), a hormonal imbalance that the PCOS Awareness Association says affects 10 million women worldwide. When the body makes excess “male” hormones called androgens, this is often accompanied by an increase in acne.

Your doctor may suspect PCOS if you have acne along with irregular periods or acne that flares up just before your period, says Dr. Reynolds. Even if PCOS isn’t behind your breakouts, your acne may be saying something else about your body—find out what your acne says about your health.

Close up Allergy rash, Around Back view of human with dermatitis problem of rash ,Allergy rash and Health problem.

You’ve developed a weird rash

Something relatively benign—such as a new laundry detergent or metal buttons on your pants—can be behind a new rash. Your dermatologist can help you figure out what to avoid and do a patch tets if needed.

Tick bites can also be responsible. Five different types of tick diseases cause telltale skin rashes, from the bullseye of Lyme and STARI (southern tick-associated rash illness) to small pink spots dotting wrists, forearms, and ankles that are associated with Rocky Mountain spotted fever. Watch out for such skin changes if you’ve been camping, hiking, or spending time outdoors in known tick areas. If you find a tick attached to you, here’s how to safely remove it.

ill allergic rash dermatitis eczema skin texture

You have a weird rash, part II

Starting a new medication can come with potential reactions. One serious problem: an allergy called “drug reaction with eosinophilia and systemic symptoms” or DRESS syndrome, a potentially life-threatening condition marked by a rash and an inflammation of the liver, heart, and lungs.

The American Academy of Allergy, Asthma & Immunology notes that while “almost any drug could cause DRESS,” the ones commonly associated with this are antibiotics, and gout and seizure medication. The Academy also states that this rash can appear two to eight weeks after starting the med. Watch out if you have a rash accompanied by fever or swelling of lymph nodes. (Don’t miss these medical reasons for rosy cheeks.)

Close-up Of A African Woman Suffering From Itching

You’re so, so itchy

If you have dry skin—especially in the winter months—you may be used to feeling itchy. But when a good moisturizer provides no relief, it could a skin problem that is a sign of a serious disease.

Itchiness can be caused by some cancers like leukemia and lymphoma, as well as liver disease and kidney failure. If itching is all over your body, is severe, comes out of nowhere, or is so bad you’re losing sleep because you’re so uncomfortable, talk to your doctor, says Dr. Reynolds. Itchiness with night sweats, fevers, and unexplained weight loss are other red flag symptoms, she says.

For run-of-the-mill itchy skin, try these home remedies.

Young beautiful freckles woman face portrait with healthy skin
Irina Bg/Shutterstock

There’s a new freckle on your face

Early melanomas may appear like a new freckle for the first weeks or months, says Dr. High. But if it’s a malignant form of skin cancer, the spot won’t stay freckle-like for long—it will keep growing.

It’s the “E” in the ABCDE’s of skin cancer,  for “evolving,” indicating a mole that changes in characteristics such as size, shape, and color. Suspicious moles need to be checked out by a dermatologist.

But don’t stop looking at your skin just because you visited a dermatologist. The American Academy of Dermatology recommends regular at-home skin checks. They encourage you to check your entire body to include your palms, soles, and even between your toes.

A skin welt
Scott Leman/Shutterstock

There are tender red bumps under your skin

While the gut and skin may not seem all that connected, they are. (Check out these secrets your gut is trying to tell you.) Conditions like inflammatory bowel disease (IBD) can sometimes affect your skin. Painful red nodules may appear on your legs; they’ll also feel deep in the surface of the skin, explains Dr. Reynolds. The condition is called erythema nodosum and may appear during a flare-up of symptoms, such as persistent diarrhea or bloody stool.

Beads of sweat are forming on the back. Disposition to sweating or perspiring.
Anna Lo/Shutterstock

Your skin is sweaty and ruddy

Unless you’re relaxing in a sauna or living in the tropics, this may be a sign of an overactive thyroid. In people who have hyperthyroidism, their metabolism is revved up. This can translate to being hot and flushed (particularly when no one else in the room is).

Your doctor should question you about other symptoms that could signal thyroid dysfunction, like weight loss or difficulty sleeping. Here’s how to know when to get your thyroid levels checked.

close up of a big lower leg bruise
Sirada Wichitaphornkun/Shutterstock

Your lower legs are swollen and red

When someone is suffering from congestive heart failure, their weakened heart struggles to keep the blood moving against the pull of gravity. As a result, the blood can pool in your legs, explains Dr. High.

Seeing deep lines after taking off your socks is another sign, he says. That said, congestive heart failure is most likely to affect the elderly; if you’re a young person and have sock lines, your socks just might be too small. But you should still be aware and catch the silent signs of heart failure.

Xanthelasma on the skin of the eyelids
Nau Nau/Shutterstock

There are yellow bumps under your skin

When seen on joints, hands, feet, and glutes, yellow bumps may be fat buildup under the skin, says Dr. High. Called xanthomas, these bumps are a sign that your cholesterol or other blood fats are too high.

They can also indicate diabetes, pancreatitis, and even some cancers. But don’t fret; here’s how you can get rid of these bumps.

Macro dry skin (ichthyosis) detail
iMoved Studio/Shutterstock

Think of the obvious first

Though skin problems can be a sign of a more serious illness, especially when saddled with dry skin or itchiness, don’t jump to a worst-case scenario, says Dr. High. If you’re itchy, first try a moisturizer. If you get hives, take an antihistamine or try a hydrocortisone cream. Then if the problem doesn’t clear up quickly, it may be time to see your doctor.

Dermatologist examining patient in clinic, closeup
Africa Studio/Shutterstock

When you should definitely see a doctor

Not every skin change is cause for alarm. But if you have new rashes that don’t go away in a week or two or are accompanied by pain, fevers, puss collection, or chills, or they coincide with other symptoms mentioned, see your doctor, advises Dr. Reynolds. If you’re still not sure, here are 10 times you need to see a dermatologist STAT.

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